ok, i am looking for a "cheat-sheet" if you will. i don't know what else to call it.

does anyone have any data on how to use an IOR scope on a .308? what i'm getting to, is that i am a pure novice at long range shooting, so i don't yet know how to use the hash marks to range a given target's distance. i will learn that from Flea when i get the funds, but for now.... is there any site that i can get data from to learn what hash mark to use at a particular distance using a certain grain bullet? (175 most likely). you know....if the target is 400 yards use the 4th hash mark down from zero, or if it's at 700 yards hold center between the 6th and 7th hash. i'm not looking for anything too precise, but at least a decent ballpark??? i have a rangefinder so i will know the distance to the target. i'm just tryig to figure hold over.

does anyone know where i could find such info?

i've googled, but i keep getting trajectory charts, and no useful info on holdover.

TIA

Paging Colt45guy.... He worked up a ballistic chart for me and my new IOR. (it was a little different from his due to mine having 1/2" clicks)
I thin the original he had would help you plus he really good at explaining how to use that thing.
I'm sure he'll see this and be along shortly.

this is a little difficult to answer concisely because basically, every rifle/ammo load is going to shoot differently, based on barrel length, tightness of the bore and chamber, ambient temps....


for a ballpark set of figures, you're going to need to know the ballistics coefficient of the projectiles, muzzle velocity, elevation above sea level and temperature. Or, you can just go out and shoot at various ranges and write down what you see happening.






the way the IOR reticle is set up--if you have the MP8 isn't too difficult.

the tiny dot in the middle is .10 mil. If you have the new style MP8, there's gonna be a space between the dot and where the cross hair starts. That space is 1 mil. The little hash marks are 1 mil, the bigger marks are 2 mils, and the REALLY big hash marks are 10 mils.

If you know that 1 MOA is approximately 1 inch at 100 yds, it's easy to figure out that at 200 yds, 1 MOA = 2 inches. 1 MOA = 3 inches at 300 yds, etc....If you know your range, and you know what your ammo does, it's easy to use hold overs, but you're gonna be having a harder time if there's any wind because your holdover is going to be off into one of the blank quadrants of the scope.

eta: something I just learned....the dots or hash marks are NOT MOA as I previously stated--I've corrected my previous statement....they're milliradian marks, and they are not equal to MOA. But they can be used to quickly judge MOA....1 mil = apprx 3.5 MOA. If you're zeroed and shooting at something at 400 yds, 1 MOA would be apprx 4 inches, right? By using the next mil mark (below your zero) as your hold over, your point of aim will be approximately 14" higher at 400 yds.



(you'll learn this stuff at your class--damn, I envy you! I just don't have the time to take classes like I want to)


shoot me your email address in a pm and I'll send you an Excel dope sheet I made up for one of my rifles and a couple of loads....it probably won't work on your rifle due to the short barrel on mine, but it'll give you an idea what you're looking for

This post has been edited by Colt45Guy: November 8th 2007 4:49 PM

If you do not figure it out send me the following data and I will print you up a sheet from Exbal.

Data:
state, city(or give me ALT, TEMP, HUM)
barrel length
ammunition (manufacture, caliber and bullet weight...example .308 175 BalckHills)

This will not be perfect but it will get you close enough to figure out and fine tune your own dope.

Chad

thanks Chad! Welcome to the forum--looking forward to learning some things from you!

...prepare to be disappointed

Chad

well thanks chad!

lets see....
- i live right outside lynchburg, va
- 26 inch barrel
- .308 175 BlackHills is probably what i'll be shooting with

i appreciate you doing that. my rifle is set to be here tuesday (keeping my fingers crossed on that one), and season opens on saturday, so i'm not gonna have a lot of time to play with it, considering it is dark when i get home after work. i will have time to zero it at 100 yards, but that's gonna be about it. it would be nice to have at least a ballpark figure in my head.

thanks again chad.

Then we're all in the same boat.


I'm a novice myself....I only got interested in long range shooting about a year ago, and the majority of my 'knowledge' is purely theoretical or book learning--definitely not practical. We don't have any ranges with more than 200 yds without driving 3+ hrs. Between the price of ammo and the price of gas, I don't get to stretch my rifles' legs very often. As such, please feel free to correct me if I post bad info.




(your avatar---that's a Horus reticle?)

Here 'ya go:

Mil-Dot Simulator

Mil-Dot Master

How to Get the Most out of your Mil Dot Reticle

Yo!

email me so I can send you an Excel sheet. cdrayer"at"rapidreticle.com

Good on you. Need to start somewhere.

The reticle is our RR800.

Chad

THAT'S WHERE I'VE SEEN THAT!!!!!!!! I'm still looking forward to seeing one of those up close! Thanks!

Louie--thanks for posting the links!

yes, thank you to EVERYONE!

chad, i'll send you an email when i have a more steady internet connection. at home i'm fighting with dialup and it sucks. if you can beat me to it, my email is hsracer201@aol.com. for all your help.

hey if you want the army issue powerpoint for designated marksman, I can send it to you it covers most of what you were talking about

sure thing, anyone can email anything they can that will help. my email is *suprise* hsracer201@aol.com

would you mind sending me a copy also? I'll tack it here





Colt45guy@bellsouth.net

This post has been edited by Colt45Guy: November 12th 2007 4:22 PM